It's better to tell the actual situation to know if he needs more emotional help. They tend to hide it but the real thing is that they need help from someone but they are shy to tell it because they will be judged as they thought.
I agree, but the way to never force him to tell his gambling defeat, we can divert the conversation as if we have also experienced a high loss and are willing to accept someone's motivation not to repeat the same thing in the future, so that way is more effective to make he is open to talk about the details of his losses.